Can a teacher take a students and look through all phone photo's and text?

Apparently someone in my son's class took a video of the teacher during class and the teacher found out. She thought it was my son. She took his cell phone and ipod and gave it to the assistant principal of the school (my son did not do it). The assistant principal looked through all my son's photo's. There were nude photo's of my son and his girl friend. (these pictures were taken with the phone and were never sent) He called me and my son for a meeting and inberest my son and laughed. He kept the phone for 2 days and called (CHILD PROTECTIVE SERVICES) on me. He also tried forcing my son to tell the girlfriend's name, even though she does not go to the same school, and told him that he might be arrested for child pornography. He ended up not calling the police, but I got a visit from CPS.